Oocyte CryopreservationOocyte cryopreservation is an investigational procedure offered to females older than age 16, who have been diagnosed with cancer that may affect fertility. Cryopreservation provides indefinite storage of eggs that, if viability is maintained, are available for use at a later time, in the attempt to initiate a pregnancy using assisted reproductive technologies. The stored egg can be then used to initiate a pregnancy.
Normally, the female produces one mature egg every 28 days. The probability of successful cryopreservation and fertilization with only one egg is very low. To increase the chances of successful egg survival and fertilization after oocyte cryopreservation, females electing to cryopreserve oocytes undergo ovarian stimulation to promote multiple eggs.
After the oocytes are harvested they will be cryopreserved with a technique called vitrification. The process of vitrification removes water that is normally found within eggs and replaces it with solutions called cryoprotectants. The eggs are then placed in a vessel, sealed, and cryopreserved. Once cryopreserved, the eggs will be stored in liquid nitrogen at -196'C. The thawing process entails warming the vessel and its contents, and reversing the cyropreservation process by placing the eggs in several distinct solutions that remove the cryoprotectants and restore water into the eggs.
To initiate a pregnancy, the cryopreserved and warmed eggs will be inseminated by intracytoplamic sperm injection (ICSI). If fertilization occurs, embryos will be grown and can be transferred into the woman's uterus in an attempt to establish a pregnancy.